Gasket



July 8,1947. H. w. GOULD 2,423,771

GGGG ET Patented July 8, 1947 warn GASKET Harold W. Gould, Evansto CranePacking Company,

poration of Illinois Ill, assig-nor 'to Chicago, 111., a cor-Application September 17, 1945, Serial No. 616,700

3 Claims. (Cl. 288-2) This invention relates to gaskets and'particularlyto gaskets for use in applications where no provision is made foradjustment of the pressure on the gasket after it is installed. Forpurposes of illustration, this invention will be described withreference to'a gasket for effecting a seal between the cylinder body andcylinder head of a Diesel engine at the water jacket.

There are many materials available for use as gaskets which operate verywell as long as expansion and contraction can be compensated for bymechanical means, or gasket remains constant. Such materials, however,lose their sealing ability should the pressure be relieved, for example,as a result of the expansion of the bolts or other means used to holdthe parts of the device together. Such materials have not been found towork very well when installed as gaskets in the cooling water system of8. Diesel engine. In order to compensate for the thermal expansion ofthe parts to be sealed, it has been proposed to use a resilientcomposition as the gasket material, this composition being preferablyrubber or one of the synthetic rubbers. The rubber gasket haslimitations as to temperature, however, which cause it to deterioraterather rapidly. It is also well known that rubber, either natural orsynthetic, when heated above 300 Fahrenheit will become hard and brittleand will lose its ability to follow the thermal expansion andcontraction of the parts to be sealed.

, The principal object of this invention is to provide a gasket for adevice in which no provision is made for adjustment of the pressure onthe gasket after it is installed, which gasket will provide an effectiveseal at all times under these conditions.

A more specific object of this provide a gasket which is made of aplurality of materials, the-material forming the main body of the gasketbeing a, plastic packing comprising a mixture of asbestos, graphite andrubber, and another being a mixture of cork, graphite and apolyisobutylene having a relatively high molecu lar weight with a loosejacket of woven cotton threads.

Yet another object of this invention is to provide a gasket for the usehereinabove described, said gasket being comprised of a main body of a.plastic packing comprising asbestos, graphite and rubber, an outerprotective ring of lead and a groove filled with a packing substancecomprising essentially cork, graphite and a polylso= butylene. v

Yet another object of this invention is a method of forming a ring for agasket comprising a main body of relatively hard material, a protectivethe pressure on the invention is to metallic edge and a surface of tackypacking material.

These and other features and objects of this invention will becomeapparent from the following detailed description when taken togetherwith the accompanying. drawings, in which Fig. 1 is an elevation insection of a forming die for forming a, ring or gasket in accordancewith this invention, the die being shown in par= tially closed position;

Fig. 2 is a quarter section corresponding to Fig. 1 showing the die inclosed position;

Fig. 3 is a section through a ring or gasket which has been completelyformed and filled; and

vFig. 4 shows the manner in which the ring of Fig. 3 may be applied tothe cylinder head of a Diesel engine.

Referring now to Fig. 1 for a detailed description or this invention,there is shown a lower die member l0 and an upper die member H in apartially closed position. Said lower die member i0 is comprised ofablock in a circular opening it. The ing it is substantially equalameter of the finished gasket or ring. The internal diameter of the ringis determined by a pin it located centrally of opening it. Between pinit and block I? is a ring i5 having a head 6% formed in the uppersurface thereof. Said seed is located in such a manner that the apexthereof will be closer to pin It than to block l2. Ring i5 forms theunder surface oi. the finished gasket. The upper die is comprised of aring it secured to or removable with a hollow cylindrical upper dieplunger 18. Said ring H is formed with an internal conical surface itwhich is utilized to form the exterior conical surface. of the finishedgasket.

The function of the die is to form an endless ring from suitablematerial, one surface of the ring being conical, the other beingsubstantially radial with a'groove formed therein to receive a sealingmaterial of a diflerent character. The die also performs the function ofuniting a pro tective endless ring of soft plastic metal to the outsidetip of the finished ring. To this end when it is desired to form a ringwith the dies shown in Fig. an endless ring 20 of plastic metal such aslead is first dropped into the die to assume the position shown nFig. 1. I Next, an endless ring 2! of a plastic packing made preferablyof asbestos fibres and rubber with metallic particles dispersed thereinis dropped into the cavity be tween pin it and block l2. After endlessring diameter of open to the outside diand rin 25 of the plasticmaterial are in place in the cavity the upmamsition shown. in Fig. L.

die it descends to the it will. he observed l2 having formed therering al i narrower than the finished height of the rlng, the material at theouter edges of the ring being squeezed radially inwardly and upwardly tocompletely fill the space between lower ring l5 and upper ring 19 of thedie. In the process of closing the dies, endless ring 20 of plasticmetal will be deformed as shown in Fig. 2 and will become firmlyembedded in the plastic material.

After the ring is formed in the dies, it is removed therefrom and itwill be found to have a groove 22 in the surface 23 which is normal tothe axis of the ring. Said groove 22 is unsymmetrical sothat the apexthereof is located at a point closer to the center surface 24 of thering than to the apex thereof. This will insure the presence of a properamount of material above the apex to give the finished ring thenecessary strength. The groove 22 is then filled with a ring of packingmaterial comprising cork, graphite and a poly'isobutylene of arelatively high molecular weight, enough of the material being imbeddedinto the groove so that it projects slightly from the surface 23.

Referring now to Fig. 4, the finished gasket 20 is shown as it wouldappear when installed in the cylinder head of a Diesel engine. There isshown for example the body or block 28 of the engine having a cavity 21which constitutes the combustion chamber and an adjacent cavity 28 whichconstitutes the coolin water jacket for the engine. The top of thecombustion chamber 2'27 is covered by a cylinder head 29 which is coredas at 30 to form a cooling water chamber. The hollow chamber 30 is incommunication with the chamber 28 by means of a metallic cylinder Ellwhich in turn is in communication with a passageway 32 leading directlyinto the top of chamber 28. Gasket 25 is inserted between the body itand 'head 29 around cylinder 8 l.

A considerable space is provided between the cylinder head 29 and theengine body 28 because of the presence of a soft metallic gasket 33 madeof copper or similar metal near the internal combustion chamber 21. Itwill be observed that cylinder head 29 is retained on block 263 by meansof a plurality of bolts 35 which are tightened initially and are notthereafter tightened except after the engine is serviced, as for examplewhen the cylinder walls are cleaned or rebored. Thus when the pressureis applied by bolts 3% upon gasket 25 it may be relieved by subsequentexpansion of the bolts and consequently were it not for the presence ofa seal such as gasket flt-between the head and cylinder block, thecoolant would soon escape from between the head and block to theexterior. With the ring Eli interposed between the head and body aroundcylinder 3i, however, the escape of coolant is completely preventedregardless of the number of cycles of heating and cooling to which theengine may be put.

The function of the plastic body 2i of the ring is to take the generalform of the cavity formed by the top of cylinder block 20 and cylinderhead 20. The insert 35 is compressed with the plastic material 2i and ifthe pressure becomes too great the material of the insert has tendencyto escape around the top of cylinder block 25. The presence of ring 20however prevents this and also protects the edge of the plastic andrelatively soft material ti from the destructive influences of theescaping substances of the insert. After the bolts 35 are tightened, theWedge action of the apex of the ring 26 is such oil that a considerableforce is developed tending to hold ring 2| against the cylinder 3! andthe cylinder head 29. This same force, however, is applied normal to thebottom urface of ring 25 and hence the unit loading on the bottomsurface is less than the unit loading on the conical upper surface.Thus, should a separation take place between cylinder head 29 andcylinder block 26, the upper surface of ring 25 will tend to adhere tothe cylinder head 29 and the fiat surface 28 will tend to rise oil thetop of cylinder block 28. I have found from tests that the greatesttendency to leak occurs on thi bottom surface rather than on the conicaltapered surface. It is for this reason that a substance which is tacky.such as the material of insert 35 has been inserted into the groove 22.This tacky substance will maintain a seal between the cylinder head 29and the cylinder block 26 even though a slight separation between thering 25 and block 28 takes place.

It is understood that the foregoing description is merely illustrativeof a preferred embodiment of this invention and that the scope of theinvention therefore is not to be limited thereto but is to be determinedby the appended claims.

What is claimed is:

l. A gasket comprising a ring having a body of plastic sealing materialwhich has insufllcient resilience to follow the expansion andcontraction of the elements to be sealed, said body including asbestos,a flaky material and rubber, and means for effecting a seal despite suchexpansion'and contraction, said means comprising an insert in the ringof soft tacky material which is capable of following the expansion andcontraction of the elements to be sealed, said material including as itsmajor constituents, cork and polyisobutylene.

2. A gasket comprising a ring having a body of plastic sealin materialthe .principal ingredients of which are asbestos, graphite and rubber,said ring having a radially disposed side and tapered on the other side,with a groove formed in the radially disposed side, and a tackysubstance retained within the groove, said substance including cork andpolyisobutylene.

3. A gasket adapted to effect a. seal between a cylindrical surface, asurface substantially normal to the cylindrical surface and a surfacewhich is conical and connects the cylindrical and normal surfaces, saidgasket comprising a body of plastic sealing material havingsubstantially the configuration of the space defined by the said threesurfaces, said plastic sealing material being comprised principally ofasbestos, graphite and rubber, the surface on the gasket correspondingto the normal surface having a groove therein, and a tacky substanceretained within the groove, said substance including cork andpolyisobutylene and said substance contacting the normal surface.

HAROLD W. GOULD.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Great Britain 1922'

